How long does it take a 750W heater to raise the temperature of 1kg of water from 20oC to 50oC [specific heat capacity of water = 4200Jkg-1K-1]

How long does it take a 750W heater to raise the temperature of 1kg of water from 20oC to 50oC [specific heat capacity of water = 4200Jkg-1K-1]

Answer Details

Heat energy = Elect. energy

mc$\theta$ = power x time

1 x 4200 x (50 - 20) = 750 x t

t = 168s